The present invention generally relates to electrically operated locking systems for doors and the like.
Electrically operated locking systems for doors, for example, safety or security room doors, generally comprise a bolt locking unit installed on the inside of the door which is electrically coupled to a control unit which may be installed on the outside of the door or elsewhere, for example, at a central control room.
The control unit may be any of a variety of types, including those types using magnetic cards or keyed-in pass codes. The function of the control unit is to ensure that only authorized persons may operate the locking unit.
Normally, following input at the control unit, typically by key, numbered combination or password, an electrical pulse or current activates the bolt unit which withdraws the bolt from the door frame to unlock the door or inserts the bolt unit into the door frame to lock the door.
Such electrically operated systems tend to have sensitive internal mechanisms which are easily damaged if attempts are made to operate the bolt unit when the door is open or when it is closed for locking or unlocking thereof, but is not properly seated.
It is known to employ devices, such as micro-switches or relays, which are operatively coupled to the locking system to prevent activation of the bolt unit whenever the system is not ready, and often also to display whether the lock is ready to be activated.
Furthermore, in certain types of systems, these devices are used to automatically operate the locking system upon the slamming of the door.
However, several disadvantages have been experienced with respect to such conventional systems. First, the mounting and installation of the micro-switches and other equivalent devices may be complicated and expensive, mainly because of the high level of precision that is required for the proper functioning thereof. Secondly, even after proper installment, there is always the need for conducting fine adjustment operations. Thirdly, the devices may be damaged or otherwise become malfunctioned during prolonged use or by tampering therewith.